Canna are tender summer blooming bulbs native to tropical and subtropical regions, according to the University of Minnesota. Canna, also called canna lilies, have large leaves and striking flowers on long stalks. They are only hardy to USDA Hardiness Zones 9 though 11, so they cannot survive harsh winters in much of the U.S. If you have canna lily bulbs planted in your yard, you have to prepare them properly for winter, or they will not bloom the next year.
Cut back the canna's foliage once it dies back due to frost. Cut back the stems about 4 to 5 inches.
Dig up the bulbs with a spade, being careful not to sever the roots, and lay them out to dry in a dark room. It may take one to three days for the bulbs to fully dry.
Prepare a box with a 3-to-4-inch layer of sand in it. Place the dry canna bulbs in the box, and cover them with the sand.
Place the box in a dry, dark place with a steady temperature of around 40 to 50 degrees Fahrenheit.